package ninezhang;

public class TestCircle {
	public static void main(String[] args) {
		Circle circle1=new Circle();
		System.out.println("The area of the circle of raduis "+circle1.radius+" is "+circle1.getArea());
		
		Circle circle2=new Circle(25);
		System.out.println("The area of the circle of radius "+circle2.radius+" is "+circle2.getArea());
		
		Circle circle3=new Circle(125);
		System.out.println("The area of the circle of radius "+circle3.radius+" is "+circle3.getArea());
	
		circle2.radius=100;
		System.out.println("The area of the circle of radius "+circle2.radius+" is "+circle2.getArea());
	}
	
}

class Circle{
	double radius;
	Circle(){
		radius=1;
	}
	
	Circle(double newRadius){
		radius=newRadius;
	}
	
	double getArea() {
		return radius*radius*Math.PI;
	}
	
	double getPerimeter() {
		return 2*radius*Math.PI;
	}
	void setRadius(double newRadius) {
		radius=newRadius;
	}
}